Feeder devices for linear raw dough blanks—such as raw dough strands pre-formed for pretzel production—have been known from prior art. Apparatus of this kind usually precedes a device for processing the raw dough blanks, such as a pretzel looping device.
Before the raw dough blanks can be and are processed by means of the device intended therefor, it usually is necessary, however, to stretch, measure or size, and align them. Further, means are frequently needed to sort out under-size or over-size blanks as processing devices usually require blank size to be within pre-determined limits.
Due to this necessity of stretching, measuring or sizing, and aligning the raw dough blanks, it has been known from prior art to provide between the feeding device and processing apparatus additional equipment capable of performing such stretching, measuring and aligning. The additional equipment, which increases the manufacturing and installation cost for the system as a whole, and the considerable delay caused by the additional steps in the production of the raw dough blanks between such feeding and the processing, constitute a distinct drawback.
On this basis, the object underlying the present invention is the provision of feeder means for raw dough blanks, especially raw dough strands pre-formed for pretzel production, the use of which greatly simplifies and accelerates the production to be based on such bake-off items.
In particular, it is desired to stretch, size and align the raw dough blanks as they are conveyed. Further, the inventive feeder apparatus is designed to enable under-sized or over-sized raw dough blanks to be sorted out before they can be passed on to processing apparatus.
The invention is intended also to propose a method of feeding raw dough blanks to equipment for processing them, with the execution of said method enabling the raw dough blanks to be stretched, sized and aligned as they are conveyed and fed to such equipment.
This object is attained for feeder means wherein a first conveyor belt and at least one second conveyor belt are arranged sequentially one after the other, with the raw dough blanks disposed on the first conveyor belt at the beginning of the feeding process and being transferred from said first conveyor to a second conveyor belt, and wherein the speed of the second conveyor belt is higher by a given amount than the speed of the first conveyor belt, whereby raw dough blanks, when being transferred from first conveyor belt to the second conveyor belt, are stretched and aligned to be parallel with the direction of movement of second conveyor belt. The following description also teaches a method of feeding raw dough blanks to the apparatus for processing them. The description also teaches additional inventive developments and advantages.
Accordingly, the invention proposes feeder apparatus for raw dough blanks, especially raw dough strands pre-formed for pretzel production, which comprises a first conveyor belt and at least one second conveyor belt, said conveyor belts arranged sequentially one behind the other, with the dough blanks disposed on the first conveyor belt as the feeding process begins and being transferred from the first conveyor belt to the at least one second conveyor belt.
In accordance with the invention, provisions are made for the speed of the at least one second conveyor belt being higher by a given amount than the speed of the first conveyor belt. This ensures advantageously that the dough blanks during the transfer thereof from the first to the second conveyor belt are stretched and aligned in parallel with the direction of movement of said second conveyor belt, as each dough blank is pulled ahead by the second and faster conveyor belt, resulting in the dough blanks being stretched and aligned as they are transferred.
At the beginning of the feeding process, the dough blanks may be arranged in parallel with the direction of movement of the first conveyor belt. Alternatively, the dough blanks may be arranged in a direction substantially non-parallel with the movement of the first conveyor belt and may instead move at an angle to the longitudinal axis of the first conveyor belt, and/or they may be shaped to be non-linear.
Within the framework of an advantageous further development of the invention, the adhesive friction coefficient of the at least one second conveyor belt may be selected to be higher than the first conveyor belt's so that “idling” of the second conveyor belt may be avoided especially in the case of higher-weight dough blanks.
Further, and in accordance with a further development of the invention, the inventive transfer device includes a sensor which detects the end turned away from the first conveyor of a raw dough blank transported by and arriving on the second conveyor and is damped by it, with the sensor maintaining its damped response until the raw dough blank is not within the sensor's detection range any longer. If a plurality of second conveyors is provided, each such second conveyor has a sensor associated with it.
In accordance with the invention, the length of the stretched raw dough blank aligned in parallel with the conveying direction of the second conveyor belt is determined in a controller which is coupled with the sensor and evaluates the period of time for which the sensor is damped, as well as the conveying speed of the second conveyor belt. In case the length so determined of the raw dough blank is greater or smaller than a target length plus/minus a prescribed length offset, the second conveyor belt is controlled to make the blank reach the end of the second conveyor belt where continued circulation thereof causes the blank to be transferred to a container or to another conveyor, resulting in it being sorted out.
If the length so determined of the raw dough blank corresponds to the target length plus/minus a prescribed length offset, the invention provides for the raw dough blank to be transported until it assumes a centered position relative to, or on, the longitudinal axis of another conveyor or of a transfer chute to be passed on to means for processing the raw dough blank. Preferably, such other conveyor or transfer chute is disposed at right angles to second conveyor belt 2. Also, the length offset may assume a value of zero.
Once the raw dough blank has reached this position the first and second conveyor belts are stopped and the raw dough blank is transferred by suitable means from the second conveyor belt to the other conveyor or the transfer chute. Following such transfer of the raw dough blank, the conveyor belts are re-activated to move.
The means for transferring the raw dough blank to the other conveyor or to the transfer chute may have the form of a pusher device adapted to be driven mechanically, pneumatically, hydraulically or electrically.
Alternatively, transfer to the transfer chute or to the other conveyor of a raw dough blank disposed centrally relative to the longitudinal axis thereof may be effected by the second conveyor belt having the form of a “V-belt” comprising a pair of belt runs disposed for transporting the raw dough blanks in a parallel and contiguous relationship and driven with the same speed, said two conveyor belts having a first position in which their top runs span a common plane for transporting said raw dough blanks, and a second position rotated about an axis parallel with the longitudinal axis, or about the longitudinal axis thereof, in which the top runs of the conveyor belts assume a given angle relative to each other so that the raw dough blanks may be transferred by gravity to the underlying transfer chute or to the underlying other conveyor. After a transfer so effected of the raw dough blanks, both conveyor belts re-assume the first position in which they are parallel and contiguous with each other.
The inventive concept results in a transfer arrangement which operationally enables the raw dough blanks to be stretched, sized and—if desired—to be sorted out in transfer. In this context, it is noted that it is not possible to sort out dough blanks in the stretching and aligning devices known from prior art.
In accordance with the invention, the first and the at least one second conveyor belt may have the same longitudinal axis or longitudinal axes parallel with each other, or the conveyor belts may be disposed in any desired angular relationship. It is possible furthermore that the first and the at least one second conveyor belts are driven by a single drive unit, with different conveyor speeds obtained in this case by reducing or increasing the drive unit's output speed by means of suitably dimensioned gears, for example. Alternatively, the conveyor belts may each have a separate drive unit associated therewith.
Within the scope of an advantageous further development of the invention, and for feeding a plurality of devices for processing the raw dough blanks, the first conveyor belt may be followed a plurality of second conveyor belts each associated with a separate device for processing raw dough blanks. In this case, the width of the first conveyor belt is chosen so that the raw dough blanks may be transferred simultaneously to the plurality of second conveyor belts; such second conveyor belts may each be disposed at any given angle relative to the first conveyor belt.